diff --git a/graphene_django/types.py b/graphene_django/types.py
index 374d270..80e54bf 100644
--- a/graphene_django/types.py
+++ b/graphene_django/types.py
@@ -133,7 +133,7 @@ class DjangoObjectType(ObjectType):
             return True
         if not is_valid_neomodel_model(type(root)):
             raise Exception(('Received incompatible instance "{}".').format(root))
-        return isinstance(root.__class__, cls._meta.model)
+        return isinstance(root, cls._meta.model)
 
     @classmethod
     def get_node(cls, info, id):